Effect of oxygen concentration on the senescence and energy metabolism of cut carnation flowers

The effect of O2 concentration on energy metabolism and senescence has been studied in cut flowers of Dianthus caryophyllus L. cv. Scania. As compared to the control (21% O2), 5% O2 delays flower senescence as well as decay of nucleotide level and AEC (adenylate energy charge). An atmosphere of 100% O2 accelerates senescence as well as the decrease of nucleotide level and AEC. While anoxia brings about a faster decrease of ATP and AEC than of total nucleotides, hyperoxia brings about a faster decrease in adenyl nucleotides than in ATP and AEC values. Petal oxygen uptake is over 90% of the maximal value under 4% O2 and saturates at 10% O2. The development of senescence is dicussed as a two phase process (first phase‐progressive and second phase‐catastrophic) triggered by the action of hyperoxia, first on the system for energy utilization and later on the system for energy production, the degradation of which seems to be linked with increase in membrane permeability and withering.